Many different shavers are available today. Shavers are available for shaving beards or hair on other parts of the body. Some shavers are designed for the male body and some for the female body and some for both. Besides shavers for humans, shavers for animals are available on the market that are particularly suited for shaving animals such as dogs. The present application relates to both human and non-human appliances.
For shaving human hair there is an optimal speed of the cutters. For rotary shaving systems this speed is in the range of 1800 to 2200 rpm. Shavers have been described that detect the presence of skin through a pressure switch or a proximity sensor that switches on the shaver when it detects skin contact in order to prolong battery life. This switching on needs to take place before the shaving heads contact the skin, because moving the shaver over skin when it is off is uncomfortable due to pulling and tugging. However, the use of a proximity sensor to achieve switching on of the shaver just prior to skin contact requires additional components.
U.S. 2012/0024552 A1 discloses an electrical power tool, in particular a lawn mower, including a motor, a motor load detecting unit, and a motor power supplying unit. The motor power supplying unit changes an amount of the driving voltage based on the motor load detected by the motor load detecting unit. In particular, the driving voltage is changed from a lower value to a higher value when the detected motor load is greater than a first threshold, and the driving voltage is changed from the higher value back to the lower value when the detected motor load is smaller than a second threshold smaller than the first threshold. Thus, the power supplying unit reduces the amount of the driving electrical power when determining that the motor runs idle.
U.S. Pat. No. 5,367,599 discloses an electric shaver provided with a motor that drives a cutter, and further provided with a motor current sensing circuit and a computation circuit which processes an output from the motor current sensing circuit. Based on the measured motor current, the computation circuit computes a thickness of the beard hairs of the user and sets the rotational speed of the motor to a lower value in the case of relatively thin beard hairs and to a higher value in the case of relatively thick beard hairs.